Nanostructuring of liquids at solid—liquid interfaces
Nanostructuring of liquids at solid—liquid interfaces
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固液界面液体的纳米结构
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
K. Kurihara
中科院分区：
文献类型：
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作者：
K. Kurihara
限制在纳米尺度空间或固-液界面上的液体分子的行为与在块体中的行为有很大的不同，这归因于液体的表面诱导结构。采用基于表面力测量的新方法研究了液体在固液界面上的结构。表面力测量和衰减全反射(ATR)模式下的傅立叶变换红外光谱相结合揭示了一种新的氢键分子结构，即醇(如乙醇)和羧酸(如丙酸)在环己烷中的二氧化硅上的大分子簇。ATR谱表明，即使在较低的乙醇浓度(如0.1mol%)下，吸附在表面的醇(或羧酸)也会形成大团簇。光谱分析表明，醇分子簇的形成涉及表面硅醇基与醇羟基之间以及醇羟基之间的氢键作用。测力结果表明，在30-40 nm范围内有长程吸力，这可以用酒精在表面的相对吸附层的接触来解释。在羧酸的情况下也得到了类似的结果。这一现象被用于在固体衬底上制备聚合物纳米膜。为了详细研究限制在两个云母表面之间的液体(液晶)分子的有序性，发展了一种剪切力共振方法。共振峰的频率和幅度对受限样品中的长程有序高度敏感，提供了关于纳米级液体从表面到本体的结构信息。这种测量被用来研究限制在云母表面之间的4-氰基-4‘-己基联苯。
The behavior of liquid molecules, confined in nanometerscale spaces or at solid—liquid interfaces, is quite different from that in the bulk, which is attributed to the surface-induced structuring of liquids. The structuring of liquids at solid—liquid interfaces was investigated by employing new approaches based on surface force measurement. The combination of surface force measurement and Fourier transform IR spectroscopy in attenuated total reflection (ATR) mode revealed a novel hydrogen-bonded molecular architecture, macroclusters of alcohol (e.g., ethanol) and carboxylic acid (e.g., propionic acid), on silica in cyclohexane. The ATR spectra showed that alcohol (or carboxylic acid) adsorbed on the surface formed macroclusters even in a low alcohol concentration such as 0.1 mol%. The spectra indicated that the cluster formation of alcohol involved hydrogen-bonding interactions between surface silanol groups and alcohol hydroxyl groups and those between alcohol hydroxyl groups. The force measurement demonstrated long-range attraction extending to 30–40 nm, which could be explained by the contact of opposed adsorption layers of alcohol on the surfaces. Similar results were obtained in the cases of carboxylic acids. This phenomenon was used for preparing polymer nanofilms on solid substrates. A shear-force resonance method was developed in order to examine in detail the ordering behavior of liquid (liquid-crystal) molecules confined between two mica surfaces. The frequency and the amplitude of the resonance peak are highly sensitive to the long-range order within the confined sample, affording information about the liquid structuring from the surface to the bulk at the nanometer level. This measurement was used to study 4-cyano-4′-hexyl biphenyl confined between mica surfaces.